The IBM 6640 printer was one of the world's first office ink jet printers. It was originally announced as the 46/40 but later renamed as 6640, as part of the Office System/6 word processing range

Word processor

A word processor is a computer application used for the production of any sort of printable material....

 in 1976.

Documents to be printed were first prepared on either on magnetic cards by a Magnetic Card Selectric typewriter, or an Office System/6 console. Magnetic card stacks were loaded via a reader attached to the left side of the printer and the device could also communicate via BSC

Binary symmetric channel

A binary symmetric channel is a common communications channel model used in coding theory and information theory. In this model, a transmitter wishes to send a bit , and the receiver receives a bit. It is assumed that the bit is usually transmitted correctly, but that it will be "flipped" with a...

 or SDLC

Synchronous Data Link Control

Synchronous Data Link Control is a computer communications protocol. It is the layer 2 protocol for IBM's Systems Network Architecture . SDLC supports multipoint links as well as error correction. It also runs under the assumption that an SNA header is present after the SDLC header...

protocols. A model of 6640 was without a Magnetic Card Deck but was hard-wired to an Office System/6 console for direct printing.

The printer itself had a large envelope drawer, and two paper drawers, each of which could handle a stack of paper up to approx. three inches thick, and up to 17 inches by 17 inches. Optional font cards were available, and installed on the planar located on the right side of the printer. Black ink was sprayed out of a single nozzle, broken into drops, and each drop was deflected by electromagnetic fields to form individual letters or symbols. Any drops not required to generate a letter were fed back into the ink system for re-use.